We seem to be coming across more dogs that have damaged tracheas. I'm sure it's from too much compulsion with an improper collar. I'm a big fan of the pinch when we end up with a dog like this (we try to avoid byuing him in the first place). I have heard of a study showing the pinch to be less damaging than the choke. I have not found it, has anyone out there seen it? Is it just a BS rumor? I don't need it to justify my thoughts, but if a study exits, it would be nice to have. Thanks.